But, since facts and figures are key, if we assume the proportion of naturalized Mexicans naturalized in California in 2011 (39% of the total) holds true for previous years, and estimate that Mexican naturalizations since 1970 were at the same average rate as between 2002 and 2010, minus the outlier year of 2008 (almost certainly an overestimate), then there were about 1.37 million Mexicans naturalized in California from 1970 to 2010. Assuming 20% died, moved out of California, are not registered voters, or are too young to vote (almost certainly an underestimate), and 60% of the rest turned out (almost certainly an overestimate), that gets us to 660,000 votes - 250,000 still unaccounted for.

Then we have to ask whether naturalization of Mexicans in California is only 39% of the total when averaged from 1970-2010. It is probably higher. Like I said, recently a greater proportion of Mexican immigration has headed to other places than California. Back in the 1980s and 1990s it was going in higher proportions to California. Also the 20% figure who have either moved or died is a little high. You have to remember that most immigrants are young and so the vast majority of immigrants from even the 1970s will still be alive. Also it's really the 1980s and 1990s where we saw a great increase in immigration. And averaged over 1970-2010, I really have to question whether there will be a net migration of immigrants from California to other states. Maybe native whites and blacks might be moving from California, I highly doubt that is the case with Hispanics or even Asians for that matter. And as for being too young to vote, if you come through legal channels, it can take up to 5-15 years to get naturalized. Many who came as kids would be eligible to vote, or at least within a few years of naturalization, in most cases. And immigration rates among the young are not that high iirc (double check me on this point though). Most immigrants tend to be from 20-40 years old. The young and definitely the old are underrepresented.

In addition to Sbane's explanation, which is a lot more compelling than "Maybe a massive number of illegal immigrants are registered to vote!", people lie about being registered to vote pretty often. About 30% of Americans in a given election year are not registered to vote; only about 20% self-report that they aren't. Even ignoring that some Americans probably incorrectly assume their registration has elapsed or gone inactive, that suggests that about 1-in-3 non-registered voters lie about it. That social desirability effect may be lesser among non-citizens, since they have a clear excuse, or it may be greater. No idea! Point is, it's really not that difficult to imagine that discrepancy could exist for completely un-sinister reasons.

Also, voter registration databases are open record. If there were massive numbers of illegal immigrant voters, do you not think this would have been noticed? That's exactly why I'm interested in hearing more about this Colorado study. It's the only legitimate way of looking into these things...but it's tough to do on a systemic basis, so I'd like to hear about the methodology.